The present invention relates to an acrylic ester compound, a polymerizable composition containing the acrylic ester compound, and a cured product and an optical component obtained by polymerizing the polymerizable composition. Furthermore, it also relates to a sulfur-containing compound useful as a starting material at the time of manufacture of the acrylic ester compound.
Inorganic glass has been widely used in various fields as a transparent optical material, because of its favorable properties such as high transparency and low optical anisotropy. However, it has disadvantages of being heavy, fragile and poor in productivity. Therefore, various organic optical materials (optical resins) have been extensively developed to replace the inorganic glass.
One of the basically most important characteristics for an optical resin is transparency. The highly transparent optical resins developed so far include polymethyl methacrylate (PMMA), bisphenol A polycarbonate (BPA-PC), polystyrene (PS), methyl methacrylate/styrene copolymer (MS), styrene/acrylonitrile copolymer (SAN), poly(4-methyl-pent-1-ene) (TPX), polycycloolefin (COP), polydiethylene glycol bisallyl carbonate (EGAC) and polythiourethane (PTU).
PMMA has excellent transparency and weather resistance as well as good moldability. However, it has disadvantages of low refractive index (nd) of 1.49 and high moisture absorptivity.
BPA-PC is excellent in transparency, heat resistance, impact resistance and refractive index. However, it has disadvantages of relatively high optical anisotropy (birefringence) and high aberration (low Abbe number), which have limited its applications.
PS and MS have high moldability, high transparency, low moisture absorptivity and high refractive index. However, they have been rarely used as optical resins, because of their disadvantages of insufficient resistance to impact, weather and heat.
SAN is relatively high in refractive index, and considered to have balanced mechanical properties. However, it is also rarely used as an optical resin, because of its relatively insufficient heat resistance (thermal deformation temperature: 80 to 90xc2x0 C.).
TPX and COP, although having high transparency, low moisture absorptivity and high heat resistance, include disadvantages of low refractive index (nd: 1.47 to 1.53), and insufficient impact resistance, gas barrier characteristics and dye-affinity.
EGAC is a thermosetting optical resin produced by polymerization of diethylene glycol bisallyl carbonate as a monomer, and has been most widely used for common spectacles lenses. It has favorable characteristics of high transparency, high heat resistance and very low chromatic aberration, but disadvantages of low refractive index (nd: 1.50) and insufficient impact resistance.
PTU is a thermosetting resin obtained by a reaction between a diisocyanate compound and a polythiol compound, and most widely used for spectacles lenses of superhigh refractive index. PTU is a very excellent optical resin having, in particular, high transparency and impact resistance as well as a high refractive index and low chromatic aberration. However, it inconveniently needs a long time for molding by thermal polymerization (1 to 3 days), and hence involves productivity-related problems to be solved.
Some of the proposals for improved productivity by decreasing a polymerization/molding time include use of acrylates or thioacrylates containing a bromine atom or a sulfur atom for radical polymerization initiated by being irradiated with light to obtain optical lenses, as disclosed by Japanese Patent Laid-open Publication Nos. 63-248811, 1-266613 and 3-217412. Moreover, use of (meth)acrylate compounds having a sulfur-containing alicyclic structure as a radical-polymerizable compound is also suggested for production of the optical lenses by Japanese Patent Laid-open Publication Nos. 3-215801 and 4-161410.
However, the resins produced, by these methods, although being able to be polymerized in a shorter time, rarely satisfy characteristics sufficient for optical lenses, which include optical characteristics (e.g., transparency, refractive index and Abbe number), thermal characteristics (e.g., thermal deformation temperature) and mechanical characteristics (e.g., impact resistance and bending strength). More specifically, when these resins are used for spectacles lenses, they have various disadvantages of, e.g., insufficient refractive index, low Abbe number though being high in refractive index, being fragile and easily broken, and being heavy for the lenses, and in addition, the surfaces of the resins are roughened or attacked by a solvent which is used for treatment, e.g., for providing a hard coat. Therefore, developments of the materials which can solve these problems have been greatly demanded.
As described above, each of the conventional optical resins involves disadvantages and problems to be solved, though having excellent characteristics. Under these circumstances, there are keen demands for development of novel optical materials which are excellent in productivity because of being polymerizable and moldable in a short time, good in thermal and mechanical characteristics, and high in refractive index and Abbe number.
It is an object of the present invention to provide an optical resin, which can be polymerizable and moldable in a short time so that it is excellent in productivity, having good thermal and mechanical characteristics, and being high in refractive index by solving the problems involved in the conventional optical resin.
The present inventors have achieved the present invention after having extensively studied to solve the above-described problems. That is, the present invention provides:
[1] An acrylic ester compound represented by formula (1): 
(wherein
xe2x80x9caxe2x80x9d, is an integer of 0 to 4;
R1 is a directly bonded single bond, an alkylene group which may have a substituent, an aralkylene group which may have a substituent, an arylene group which may have a substituent, or a xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group;
R2 and R3 are each a hydrogen atom or an alkyl group;
X1 and X2 are each an oxygen atom or a sulfur atom;
Y1 and Y2 are each an alkylene group which may contain an oxygen atom or a sulfur atom;
R4 in the xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group is an alkylene group, an aralkylene group or an arylene group; and
Y3 and Y4 in the xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group are each independently an alkylene group.
[2] The acrylic ester compound according to [1], wherein in formula (1), xe2x80x9caxe2x80x9d is 1; R1 is a directly bonded single bond, an alkylene group which may have a substituent, an aralkylene group which may have a substituent, an arylene group which may have a substituent or a xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group (wherein Y3 is a xe2x80x94(CH2)mxe2x80x94 group and Y4 is a xe2x80x94(CH2)nxe2x80x94 group (xe2x80x9cmxe2x80x9d and xe2x80x9cnxe2x80x9d are each an integer of 1 to 4)); and Y1 is a xe2x80x94(CH2)kxe2x80x94 group and Y2 is a xe2x80x94(CH2)1xe2x80x94 group (xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d are each an integer of 1 to 4).
[3] The acrylic ester compound according to [1], wherein in formula (1), xe2x80x9caxe2x80x9d is 0; and Y1 is a xe2x80x94(CH2)kxe2x80x94 group and Y2 is a xe2x80x94(CH2)1xe2x80x94 group (xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d are each an integer of 1 to 4).
[4] The acrylic ester compound according to [2], wherein the compound represented by formula (1) is represented by formula (1-a): 
(wherein R5, which is similar to R1, is a directly bonded single bond, an alkylene group which may have a substituent, an aralkylene group which may have a substituent, or an arylene group which may have a substituent; and R2, R3, X1, X2, xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d are same meanings as described above).
[5] The acrylic ester compound according to [2], wherein the compound represented by formula (1) is a compound represented by formula (1-b): 
(wherein R2, R3, R4, X1, X2, xe2x80x9ckxe2x80x9d, xe2x80x9clxe2x80x9d, xe2x80x9cmxe2x80x9d and xe2x80x9cnxe2x80x9d are same meanings as described above).
[6] The acrylic ester compound according to [3], wherein the compound represented by formula (1) is a compound represented by formula (1-c): 
(wherein R2, R3, R4, X1, X2, and xe2x80x9clxe2x80x9d are same meanings as described above).
[7] The acrylic ester compound according to [3], wherein the compound represented by formula (1) is a compound represented by formula (1-d): 
(wherein R2, R3 and xe2x80x9clxe2x80x9d are same meanings as described above).
[8] A polymerizable composition containing the acrylic ester compound according to any one of [1] to [7].
[9] A cured product obtained by polymerizing the polymerizable composition according to [8].
[10] An optical component comprising the cured product according to [9].
[11] A process for producing the acrylic ester compound represented by formula (1) in accordance with acrylate-esterification of a sulfur-containing compound represented by formula (2): 
(wherein xe2x80x9caxe2x80x9d, R1, X1, X2, Y1 and Y2 are same meanings as described above).
[12] The process according to [11] for producing the acrylic ester compound represented by formula (1), wherein the acrylate-esterification is effected by reacting a halopropionic acid or its acid halide with the compound represented by formula (2) to convert it into a halopropionic ester compound, and then by dehydrohalogenating the halopropionic ester compound into the acrylic ester.
[13] The process according to [11] or [12] for producing the acrylic ester compound, wherein the compound represented by formula (2) is a compound represented by formula (2-a): 
(wherein R5 is a directly bonded single bond, an alkylene group which may have a substituent, an aralkylene group which may have a substituent, or an arylene group which may have a substituent; xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d are each an integer of 1 to 4; and X1 and X2 are each an oxygen atom or a sulfur atom).
[14] The process according to [11] or [12] for producing the acrylic ester compound, wherein the compound represented by formula (2) is a compound represented by formula (2-b): 
(wherein R4 is an alkylene, an aralkylene or an arylene group; xe2x80x9ckxe2x80x9d, xe2x80x9clxe2x80x9d, xe2x80x9cmxe2x80x9d and xe2x80x9cnxe2x80x9d are each an integer of 1 to 4; and X1 and X2 are each an oxygen atom or a sulfur atom).
[15] The process according to [11] or [12] for producing the acrylic ester compound, wherein the compound represented by formula (2) is a compound represented by formula (2-c): 
(wherein X2 is an oxygen atom or a sulfur atom; and xe2x80x9clxe2x80x9d is an integer of 1 to 4).
[16] The process according to [11] or [12] for producing the acrylic ester compound, wherein the compound represented by formula (2) is a compound represented by formula (2-d): 
(wherein xe2x80x9clxe2x80x9d is an integer of 1 to 4).
[17] A sulfur-containing compound represented by formula (2-a): 
(wherein R1 is a directly bonded single bond, an alkylene group which may have a substituent, an aralkylene group which may have a substituent, or an arylene group which may have a substituent; xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d are each an integer of 1 to 4; and X1 and X2 are each a sulfur atom or an oxygen atom).
[18] A sulfur-containing compound represented by formula (2-b): 
(wherein R4 is an alkylene group, an aralkylene group or an arylene group; xe2x80x9ckxe2x80x9d, xe2x80x9clxe2x80x9d, xe2x80x9cmxe2x80x9d and xe2x80x9cnxe2x80x9d are each an integer of 1 to 4; and X1 and X2 are each an oxygen atom or a sulfur atom).
[19] A sulfur-containing compound represented by formula (2-c): 
(wherein X2 is an oxygen atom or a sulfur atom; and xe2x80x9clxe2x80x9d, is an integer of 1 to 4).
[20] A sulfur-containing compound represented by formula (3): 
(wherein X3 is a halogen atom; an xe2x80x9cbxe2x80x9d is an integer of 1 to 4).
The present invention will be described in detail.
The acrylic ester compound of the present invention represented by formula (1), is a novel compound characterized by the chemical structure having, per molecule, one or two dithiolan ring structures and two (meth)acryloyl groups.
The acrylic ester compound of the present invention is a novel compound characterized by the chemical structure having, per molecule, one or two dithiolan ring structures and two (meth)acryloyl groups, and useful as a monomer for a polymerizable composition, curable by being initiated for polymerization when irradiated with light: 
In formula (1), xe2x80x9caxe2x80x9d is an integer of 0 to 4, preferably 0 to 3, more preferably 0 to 2, still more preferably 0 or 1.
In formula (1), R1 is a directly bonded single bond, an alkylene group which may have a substituent, an aralkylene group which may have a substituent, an arylene group which may have a substituent, or a xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group (wherein R4 is an alkylene group, an aralkylene group or an arylene group, and Y3 and Y4 are each an alkylene group).
It is preferably a straight-chain, a cyclic alkylene group or their combination of 1 to 20 carbon atoms which may have a substituent; an aralkylene group of 6 to 20 carbon atoms which may have a substituent; an arylene group of 4 to 20 carbon atoms which may have a substituent; or a xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group.
When R1 is an alkylene-group which may have a substituent, the substituent for the alkylene group includes alkoxy, alkoxyalkoxy, aralkyloxy, aryloxy, aryloxyalkyloxy, alkylthio, alkylthioalkylthio, aralkylthio, arylthio and arylthioalkylthio groups.
When R1 is an aralkylene group or an arylene group which may have a substituent, the aromatic ring in the aralkylene group or the arylene group is preferably substituted. The substituent includes alkyl, alkoxy, alkoxyalkoxy, aralkyloxy, aryl, aryloxy, aryloxyalkyloxy, alkylthio, alkylthioalkylthio, aralkylthio, arylthio and arylthioalkylthio groups, and a halogen atom.
The aromatic ring in the aralkylene or the arylene group may be a hydrocarbon aromatic ring or a heteroaromatic ring containing a heteroatom. The heteroatom is preferably an oxygen, sulfur or nitrogen atom, more preferably an oxygen or sulfur atom, still more preferably a sulfur atom.
The R1 group is more preferably a directly bonded single bond, a straight-chain, branched or cyclic alkylene group or their combination of 1 to 8 carbon atoms, an aralkylene group of 6 to 12 carbon atoms, an arylene group of 4 to 12 carbon atoms, or a xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group, still more preferably the directly bonded single bond, the straight-chain, branched or cyclic alkylene group or their combination of 1 to 4 carbon atoms, the aralkylene group of 6 to 8 carbon atoms, the arylene group of 4 to 10 carbon atoms, or the xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group.
R4 in the xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group is an alkylene group, an aralkylene group or an arylene group, and Y3 and Y4 in the xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group are each an alkylene group.
R4 in the xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group is preferably a straight-chain or cyclic alkylene group or their combination of 1 to 20 carbon atoms which may have a substituent; an aralkylene group of 6 to 20 carbon atoms which may have a substituent; or an arylene group of 4 to 20 carbon atoms which may have a substituent.
For the alkylene group which may have a substituent, the substituent includes alkoxy, alkoxyalkoxy, aralkyloxy, aryl, aryloxy, aryloxyalkyloxy, alkylthio, alkylthioalkylthio, aralkylthio, arylthio and arylthioalkylthio groups, and a halogen atom.
For the aralkylene or the arylene group which may have a substituent, the substituent includes alkyl, alkoxy, alkoxyalkoxy, aralkyloxy, aryl, aryloxy, aryloxyalkyloxy, alkylthio, alkylthioalkylthio, aralkylthio, arylthio and arylthioalkylthio groups, and a halogen atom.
The alkylene group may contain a heteroatom, e.g., oxygen or sulfur.
The aromatic ring in the aralkylene or the arylene group may be a hydrocarbon ring or a heteroaromatic ring containing a heteroatom.
The R4 group is more preferably a straight-chain, branched or cyclic alkylene group or their combination of 1 to 8 carbon atoms, an aralkylene group of 6 to 12 carbon atoms, or an arylene group of 4 to 12 carbon atoms, still more preferably a straight-chain, branched or cyclic alkylene group or their combination of 1 to 4 carbon atoms, an aralkylene group of 6 to 8 carbon atoms, or an arylene group of 4 to 10 carbon atoms.
Of these, the particularly preferable R4 group is an alkylene, aralkylene or arylene which is not substituted.
The R4 group includes, but not limited to, methylene, ethylene, ethylidene, trimethylene, 1-methyl-1,2-ethylene, isopropylidene, tetramethylene, ethylethylene, 1-butylidene, 2-butylidene, 1,5-pentamethylene, 1,6-hexamethylene, 1,8-octamethylene, 1,4-cyclohexylene, 1,3-cyclohexylene, 1,2-cyclohexylene, 1,4-cyclohexanebismethyl, 1,3-cyclohexanebismethyl, 1,2-cyclohexanebismethyl, 1,4-cyclohexanebisethyl, 1,3-cyclohexanebisethyl, 1,2-cyclohexanebisethyl, 1,4-xylylene, 1,3-xylylene, 1,2-xylylene, 1,4-(xcex1,xcex1xe2x80x2-dimethyl)xylylene, 1,3-(xcex1,xcex1xe2x80x2-dimethyl)xylylene, 1,2-(xcex1,xcex1xe2x80x2-dimethyl)xylylene, 1,4-(xcex1,xcex1,xcex1xe2x80x2,xcex1xe2x80x2-tetramethyl)xylylene, 1,3-(xcex1,xcex1,xcex1xe2x80x2,xcex1xe2x80x2-tetramethyl)xylylene, 1,2-(xcex1,xcex1,xcex1xe2x80x2-tetramethyl)xylylene, 1,4-benzenebis-xcex2-ethyl, 1,3-benzenebis-xcex2-ethyl, 1,2-benzenebis-xcex2-ethyl, 1,4-phenylene, 1,3-phenylene, 1,2-phenylene, naphthylene, and thiophen-2,5-diyl groups.
Of these R4 groups, the particularly preferable ones are methylene, ethylene, ethylidene, trimethylene, 1-methyl-1,2-ethylene, isopropylidene, tetramethylene, 1,4-xylylene, 1,3-xylylene, 1,2-xylylene, 1,4-phenylene, 1,3-phenylene, 1,2-phenylene, naphthylene, thiophen-2,5-diyl groups.
Y3 and Y4 in the xe2x80x94Y3xe2x80x94Sxe2x80x94R4xe2x80x94Sxe2x80x94Y4xe2x80x94 group are preferably an alkylene group having a total carbon number of 1 to 8, more preferably Y3 is the one represented by xe2x80x94(CH2)mxe2x80x94 and Y4 is the one represented by xe2x80x94(CH2)nxe2x80x94, wherein xe2x80x9cmxe2x80x9d and xe2x80x9cnxe2x80x9d are each an integer of 1 to 4, preferably 1 to 3, still more preferably 1 or 2, particularly preferably 1.
The R1 group includes, but not limited to, divalent bonding groups, e.g., directly bonded single bond, methylene, dimethylene, ethylidene, trimethylene, 1-methyl-1,2-ethylene, isopropylidene, tetramethylene, ethylethylene, 1-butylidene, 2-butylidene, 1,5-pentamethylene, 1,6-hexamethylene, 1,8-octamethylene, 1,4-cyclohexylene, 1,3-cyclohexylene, 1,2-cyclohexylene, 1,4-cyclohexanedimethyl, 1,3-cyclohexanedimethyl, 1,2-cyclohexanedimethyl, 1,4-cyclohexanediethyl, 1,3-cyclohexanediethyl, 1,2-cyclohexanediethyl, 1,4-xylylene, 1,3-xylylene, 1,2-xylylene, 1,4-(xcex1,xcex1xe2x80x2-dimethyl)xylylene, 1,3-(xcex1,xcex1xe2x80x2-dimethyl)xylylene, 1,2(xcex1,xcex1xe2x80x2-dimethyl)xylylene, 1,4-(xcex1,xcex1,xcex1xe2x80x2,xcex1xe2x80x2-tetramethyl)xylylene, 1,3-(xcex1,xcex1,xcex1xe2x80x2,xcex1xe2x80x2-tetramethyl)xylylene, 1,2-(xcex1,xcex1,xcex1xe2x80x2,xcex1xe2x80x2-tetramethyl)xylylene, 1,4-benzenebis-xcex2-ethyl, 1,3-benzenebis-xcex2-ethyl, 1,2-benzenebis-xcex2-ethyl, 1,4-phenylene, 1,3-phenylene, 1,2-phenylene, 2,3-naphthylene, 2,6-naphthylene, 2,2xe2x80x2-biphenyl, 2,2xe2x80x2-diphenylether, furan-2,5-diyl, thiophen-2,5-diyl; methane-1,1-bis-thiomethyl, ethane-1,2-bis-thiomethyl, ethane-1,1-bis-thiomethyl, propane-1,3-bis-thiomethyl, 1-methyl-ethane-1,2-bis-thiomethyl, propane-2,2-bis-thiomethyl, butane-1,4-bis-thiomethyl, butane-1,2-bis-thiomethyl, butane-1,1-bis-thiomethyl, butane-2,2-bis-thiomethyl, pentane-1,5-bis-thiomethyl, hexane-1,6-bis-thiomethyl, octane-1,8-bis-thiomethyl, cyclohexane-1,4-bis-thiomethyl, cyclohexane-1,3-bis-thiomethyl, cyclohexane-1,2-bis-thiomethyl, cyclohexane-1,4-bis(methylthiomethyl), cyclohexane-1,3-bis(methylthiomethyl), cyclohexane-1,2-bis(methylthiomethyl), cyclohexane-1,4-bis(ethylthiomethyl), cyclohexane-1,3-bis(ethylthiomethyl), cyclohexane-1,2-bis(ethylthiomethyl), benzene-1,4-bis(methylthiomethyl), benzene-1,3-bis(methylthiomethyl), benzene-1,2-bis(methylthiomethyl), benzene-1,4-bis(xcex1-methyl-methylthiomethyl), benzene-1,3-bis(xcex1-methyl-methylthiomethyl), benzene-1,2-bis(xcex1-methyl-methylthiomethyl), benzene-1,4-bis(xcex1,xcex1-dimethyl-methylthiomethyl), benzene-1,3-bis(xcex1,xcex1-dimethyl-methylthiomethyl), benzene-1,2-bis(xcex1,xcex1-dimethyl-methylthiomethyl), benzene-1,4-bis(xcex2-ethyl), benzene-1,3-bis(xcex2-ethyl), benzene-1,2-bis(xcex2-ethyl), benzene-1,4-bisthiomethyl, benzene-1,3-bisthiomethyl, benzene-1,2-bisthiomethyl, naphthalene-bis-thiomethyl, and thiophene-2,5-bis(thiomethyl) groups.
The particularly preferable R1 group includes a directly bonded single bond, methylene, dimethylene, trimethylene, tetramethylene, 1,4-phenylene, 1,3-phenylene, 1,2-phenylene, naphthylene, thiophen-2,5-diyl, methane-1,1-bis-thiomethyl, ethane-1,2-bis-thiomethyl, propane-1,3-bis-thiomethyl, propane-1,2-bis-thiomethyl, propane-2,2-bis-thiomethyl, butane-1,4-thiomethyl, benzene-1,4-bis(methylthiomethyl), benzene-1,3-bis(methylthiomethyl), benzene-1,2-bis(methylthiomethyl), benzene-1,4-bis(thiomethyl), benzene-1,3-bis(thiomethyl), benzene-1,2-bis(thiomethyl), naphthalene-bis-thiomethyl, and thiophene-2,5-bis-thiomethyl groups.
R2 and R3 in formula (1) are each a hydrogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group of 1 to 4 carbon atoms, more preferably the hydrogen atom or a methyl group.
Y1 and Y2 in formula (1) are each an alkylene group which may contain an oxygen atom or a sulfur atom.
The alkylene group which may contain an oxygen atom or a sulfur atom means that its methylene group may be partly an oxa (xe2x80x94Oxe2x80x94) group or a thia (xe2x80x94Sxe2x80x94) group. Such an alkylene group which may contain an oxygen atom or a sulfur atom is preferably represented by formula (a): 
(wherein X4 is an oxygen atom or a sulfur atom; R6 is a hydrogen atom or a methyl group; and xe2x80x9cpxe2x80x9d and xe2x80x9cqxe2x80x9d are each an integer of 1 to 4).
Y1 and Y2 in formula (1) are each preferably an alkylene group having a total carbon number of 1 to 8, more preferably Y1 is the one represented by xe2x80x94(CH2)kxe2x80x94 and Y2 is the one represented by xe2x80x94(CH2)1xe2x80x94, wherein xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d are each an integer of 1 to 4, preferably 1 to 3, still more preferably 1 or 2, particularly preferably 1.
X1 and X2 in formula (1) are each a sulfur atom or an oxygen atom, preferably the sulfur atom.
Of the acrylic ester compounds of the present invention represented by formula (1), those represented by formulae (1-a) to (1-d) are particularly preferable embodiments: 
(wherein R5 is a directly bonded single bond, alkylene group which may have a substituent, aralkylene group which may have a substituent, or arylene group which may have a substituent, similarly to R1; and R2, R3, R4, X1, X2, xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d, xe2x80x9cmxe2x80x9d and xe2x80x9cnxe2x80x9d are same meanings as described above).
The specific examples of the acrylic ester compounds of the present invention represented by formula (1), are listed below, although those useful for the present invention are not limited thereto:
Moreover, the specific examples of the acrylic ester compounds represented by formulae (1-c) and (1-d) are listed below:
The acrylic ester compound of the present invention represented by formula (1) is suitably produced by a variety of esterification processes, the reactions therefor being by themselves known, using the sulfur-containing compound represented by formula (2) as a starting compound.
More specifically, these esterification processes may be represented by:
(1) reacting the compound represented by formula (2) with an acrylic ester; and
(2) reacting the compound represented by formula (2) with a halopropionic acid (e.g., 3-chloropropionic, 3-bromopropionic, 3-chloro-2-methylpropionic, 3-bromo-2-methylpropionic acid) or its acid or acid halide to convert it into the halopropionic ester compound, and then dehydrohalogenating the above product into the acrylic ester: 
(wherein xe2x80x9caxe2x80x9d, R1, X1, X2, Y1 and Y2 are same meanings as described above).
Moreover, xe2x80x9caxe2x80x9d, R1, X1, X2, Y1 and Y2 in formula (2) for the present invention are the same as those in formula (1).
Of the sulfur-containing compounds represented by formula (2), those represented by formulae (2-a) to (2-d) are particularly preferable embodiments as the intermediates for the compounds represented by formula (1), where those represented by formulae (2-a), (2-b) and (2-c) are novel compounds: 
(wherein R5 is a directly bonded single bond, alkylene group which may have a substituent, aralkylene group which may have a substituent, or arylene group which may have a substituent; xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d are each an integer of 1 to 4; and X1 and X2 are each an oxygen atom or a sulfur atom), 
(wherein R4 is an alkylene, aralkylene or arylene group, xe2x80x9ckxe2x80x9d, xe2x80x9clxe2x80x9d, xe2x80x9cmxe2x80x9d and xe2x80x9cnxe2x80x9d are each an integer of 1 to 4; and X1 and X2 are each an oxygen atom or a sulfur atom), 
(wherein X2 is an oxygen atom or a sulfur atom; and xe2x80x9clxe2x80x9d is an integer of 1 to 4), and 
(wherein xe2x80x9clxe2x80x9d is an integer of 1 to 4).
The specific examples of the sulfur-containing compounds represented by formula (2) are listed below, although those useful for the present invention are not limited thereto:
Moreover, the specific examples of the sulfur-containing compounds represented by formulae (2-c) and (2-d) are listed below:
Next, the process for producing the sulfur-containing compound for the present invention represented by formula (2) will be described.
Of the sulfur-containing compounds represented by formula (2), the one represented by formula (2-a) is typically produced by, e.g., a synthesis route of Scheme A, shown below: 
(in Scheme A, R5, xe2x80x9ckxe2x80x9d and xe2x80x9clxe2x80x9d are the same as those described earlier; and Y is a chlorine atom or a bromine atom).
In the process of Scheme A, a dialdehyde compound represented by formula (4) or its acetal derivative, or tetrahalogen compound represented by formula (5) is used as a starting compound, which is reacted with a dimercaptoalkylhydroxy compound represented by formula (6), to produce a compound represented by formula (2-a) in which X1 and X2 are each an oxygen atom. The reaction to form a dithiolan ring can be effected in a manner similar to the process described in Journal of Chemical Society (C), pp. 415-419 (1969) as the basis.
Then, the hydroxy group in the dihydroxy compound is converted into the mercapto group by a known process (e.g., reaction with thiourea under an acidic condition and hydrolyzing the resultant thiuronium salt), to produce a sulfur-containing compound of the present invention represented by formula (2-a) in which X1 and X2 are each a sulfur atom. The conversion of a hydroxy compound into a thiol (mercapto) compound is suitably effected by a known process, e.g., the one disclosed by Journal of Chemical Society, Vol. 68, 2103-2104 (1946), Journal of Organic Chemistry, Vol. 27, 93-95 (1962), or organic synthesis, V, 401-403 (1963).
Of the sulfur-containing compounds represented by formula (2), the one represented by formula (2-b) is typically produced by, e.g., a synthesis route of Scheme B, shown below: 
(in Scheme B, R4, xe2x80x9ckxe2x80x9d, xe2x80x9clxe2x80x9d, xe2x80x9cmxe2x80x9dand xe2x80x9cnxe2x80x9d are the same as those described earlier; and X5, X6 and X7 are each a chlorine atom or a bromine atom).
In Scheme B, the thioacetic acid represented by formula (8) or its salt (e.g., sodium, potassium or lithium salt) is acted on the haloalkyl aldehyde represented by formula (7) or its acetal derivative as a starting compound, to produce a compound represented by formula (9). Then, the product compound is reacted with the dimercaptohydroxy compound represented by formula (6) (representatively 2,3-mercaptio-1-propnaol or the like) in the presence of an acidic catalyst or the like to produce a compound containing a dithiolan ring represented by formula (10), and the acetylthio acid of the dithiolan-containng compound is hydrolyzed under an acidic or basic condition, to produce a compound represented by formula (11), or by formula (2) in which a is 0, X1 and X2 are an oxygen atom and a sulfur atom, respectively, Y1 is a xe2x80x94(CH2)kxe2x80x94 group (xe2x80x9ckxe2x80x9d is an integer of 1 to 4) and Y2 is a xe2x80x94(CH2)1xe2x80x94 group (xe2x80x9clxe2x80x9d is an integer of 1 to 4).
The compound represented by formula (11) is reacted with the dihalogen compound represented by formula (12) to produce a sulfur-containing compound for the present invention represented by formula (2-b) in which each of X1 and X2 is an oxygen atom.
Moreover, the hydroxy group is converted into the mercapto group by a known process (e.g., reaction with thiourea under an acidic condition and hydrolyzing the resultant thiuronium salt), to produce a sulfur-containing compound of the present invention represented by formula (2-b) in which X1 and X2 are each a sulfur atom. Such a process is described in detail in Japanese Patent Laid-open Publication No. 6-16657, as described earlier.
Of the sulfur-containing compounds represented by formula (2), the one represented by each of formulae (2-c) and (2-d) is similarly produced by a synthesis route of Scheme B. Moreover, the one represented by formula (2-c) can be also produced by acting the dithiol compound (6-1), which is the one represented by formula (6) in which xe2x80x9ckxe2x80x9d is 1, on the aldehyde compound represented by formula (7) in the presence of catalyst to produce a compound represented by formula (3), and then converting the halogen atom represented by X3 in formula (3) into the hydroxy group by a known synthesis process, e.g., hydrolysis, to produce a compound represented by formula (2-c) in which X2 is an oxygen atom. Still more, the compound represented by formula (2-c) in which X2 is a sulfur atom can be produced by converting the halogen atom represented by X3 in formula (3) into the thiol group by a known synthesis process, e.g., acting thiourea on the halogen atom to produce a thiuronium salt and hydrolyzing the salt in the presence of alkali: 
(wherein X3 is a halogen atom; and xe2x80x9cbxe2x80x9d is an integer of 1 to 4).
In the above formula (3), the halogen atom represented by X3 is preferably chlorine or bromine.
As described above, the sulfur-containing compound represented by formula (3) can be produced by acting the dithiol compound (6-1), which is the one represented by formula (6) in which xe2x80x9ckxe2x80x9d is 1, on the aldehyde compound represented by formula (7) or its acetal derivative in the presence of catalyst. This process will be described in more detail.
The aldehyde compounds represented by formula (7) or their acetal derivatives include haloalkylaldehydes, e.g., chloroacetoaldehyde, 3-chloropropionaldehyde, 3-bromopropionaldehyde, 4-chlorobutylaldehyde and 4-bromobutylaldehyde; dialkyl acetal and cyclic alkylene acetal derivatives of haloalkyl aldehydes, e.g., 2-chloroacetoaldehyde dimethylacetal, 2-chloroacetoaldehyde diethylacetal, 2-chloropropionaldehyde dimethylacetal, 2-chloropropionaldehyde diethylacetal, 2-bromopropionaldehyde dimethylacetal, 2-bromopropionaldehyde diethylacetal, 2-bromopropionaldehyde diethyleneacetal [or 2-(2xe2x80x2-bromoethyl)-1,3-dioxolan], and 2-bromopropionaldehyde dimethyleneacetal [or 2-(2xe2x80x2-bromoethyl)-1,3-dioxolan].
Quantity of the dithiol compound (6-1) for production of the sulfur-containing compound represented by formula (3), where the compound represented by formula (6-1) is acted on the aldehyde or its acetal derivative represented by formula (7), is not limited. However, it is normally incorporated at 0.1 to 10 mols per mol of the compound represented by formula (7), preferably 0.5 to 5 mols, more preferably 0.7 to 3 mols, still more preferably 0.8 to 2 mols.
The above reaction may be effected in the absence of catalyst, but preferably in the presence of catalyst in consideration of reaction temperature, reaction time or the like. The catalysts useful for the present invention include acid catalysts, e.g., protonic acids, such as inorganic acids (e.g., hydrochloric acid, hydrogen chloride, hydrobromic acid, sulfuric acid, nitric acid, boric acid and phosphoric acid), and organic acids (e.g., acetic acid, propionic acid, oxalic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid and p-toluenesulfonic acid), and lewis acids (e.g., titanium trichloride, titanium tetrachloride, tin dichloride, tin tetrachloride, zinc chloride, aluminum chloride and boron trifluoride/ether complex).
Quantity of the catalyst is not limited. However, it is normally incorporated at 0.001 to 20 mols per mol of the aldehyde compound represented by formula (7) or its acetal derivative, preferably 0.01 to 10 mols, more preferably 0.1 to 5 mols. These catalysts may be used either singly or in combination.
The reaction may be effected either in the presence or absence of solvent. The solvent, when used, is not limited so long as it is inert to the reaction. The solvents useful for the present invention include hydrocarbon-based ones, e.g., benzene, toluene and xylene; halogen-based ones, e.g., methylene chloride, chloroform, 1,2-dichloroethane, chlorobenzene and dichlorobenzene; and ether-based ones, e.g., diethyl ether, tetrahydrofuran, dioxane and diethylene glycol dimethyl ether. These solvents may be used either singly or in combination.
Quantity of the reaction solvent is not limited. However, an excessively large quantity is undesirable in view of production efficiency or the like. It is normally incorporated at 300 parts by weight or less per part of the aldehyde compound or its acetal derivative, preferably 100 parts or less.
The reaction may be also effected either under air or an inert gas atmosphere, preferably under an inert gas (e.g., nitrogen or argon) atmosphere, to prevent troubles, e.g., coloration of the product.
The reaction temperature is not limited. However, it is preferably in a range from 0xc2x0 C. to boiling point of the solvent.
The reaction time may be normally in a range from several minutes to 10 hours or more, although varying depending on reaction time or the like. The reaction can be followed by a known analytical procedure (e.g., liquid chromatography, thin-film chromatography or IR), to determine the end of the reaction.
The compound represented by formula (3) is also a novel compound, and included in the present invention. The specific examples of the sulfur-containing compounds represented by formula (3) are listed below:
Of the above-described processes for producing the acrylic ester compound represented by formula (1) by reacting the sulfur-containing compound represented by formula (2) with the acrylic acid [e.g., (meth)acrylic acid, its ester derivative, or its acid halide], the representative ones are described in more detail.
A variety of known processes as esterification processes, e.g., those described in Jikken Kagaku Koza (edited by Chemical Society of Japan), 19, 471-482 (1957), Journal of Organic Chemistry, Vol. 45, pp. 5364 (1980) and European Polymer Journal, Vol. 19, pp. 399 (1983), are cited as those useful for the present invention.
More specifically, the following two procedures can be cited as the representative ones:
((1)-a): An acid halide of (meth)acrylic acid is acted on, e.g., added dropwise to, the sulfur-containing compound represented by formula (2) with stirring in the presence of base.
((1)-b): The sulfur-containing compound represented by formula (2) is reacted with a (meth)acrylic ester derivative [e.g., alkyl (meth)acrylic ester, such as methyl, ethyl, butyl (meth)acrylic ester] for interesterification in the presence of catalyst (acidic or basic).
Of these processes, the former ((1)-a) process is more preferable, when the sulfur-containing compound represented by formula (2) has a thiol group, because of its relatively low reaction temperature to prevent addition of the (meth)acrylic acid as the other starting compound to an unsaturated double bond as the side-reaction of the desired esterification.
Quantity the acrylic acid [e.g., (meth)acrylic acid, its ester derivative, or its acid halide] to be acted on the sulfur-containing compound represented by formula (2) for the above reaction is not limited. However, it is normally incorporated at 0.1 to 5 mols per mol of the sulfur-containing compound, preferably 0.25 to 2.5 mols, more preferably 0.5 to 1.5 mols.
The reaction may be effected either in the absence of solvent or in the presence of an inert solvent. The solvents useful for the present invention include hydrocarbon-based ones, e.g., n-hexane, benzene and toluene; ketone-based ones, e.g., acetone, methylethylketone and methylisobutylketone; ester-based ones, e.g., ethyl and butyl acetate; ether-based ones, e.g., diethyl ether, tetrahydrofuran and dioxane; halogen-based ones, e.g., dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane and tetrachloroethylene; and polar ones, e.g., acetonitrile, N,N-dimethylformamide, N,N-dimethylacetoamide and N,N-dimethylimidazoline. These solvents may be used either individually or in combination.
The reaction temperature is not limited. However, it should be the level at which the acrylic acid as the starting compound or acrylic ester as the reaction product is not polymerized, and normally in a range from xe2x88x9278 to 150xc2x0 C., preferably xe2x88x9220 to 120xc2x0 C., more preferably xe2x88x9210 to 100xc2x0 C., still more preferably 0 to 50xc2x0 C.
The reaction time, which varies depending on reaction temperature, is not limited. However, it is normally in a range from several minutes to 100 hours, preferably 30 minutes to 50 hours, more preferably 1 to 20 hours. The reaction can be followed by a known analytical procedure (e.g., liquid chromatography, thin-film chromatography or IR), to determine the end of the reaction.
When the acrylic ester compound of the present invention represented by formula (1) is produced by reacting the sulfur-containing compound represented by formula (2) with an acid halide of acrylic acid, an inert gas (e.g., nitrogen or argon) may be blown into the reaction system to purge hydrogen halide (e.g., hydrogen chloride) as a by-product out of the system, or a dehydrohalogenating agent may be used.
The dehydrohalogenating agents useful for the present invention include organic bases, e.g., triethylamine, pyridine, picoline, dimethylaniline, diethylaniline, 1,4-diazabicyclo[2.2.2]octane (DABCO) and 1,8-diazabicyclo[5.4.0]undeca-7-ene (DBU); and inorganic bases, e.g., sodium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium oxide.
Quantity of the dehydrohalogenating agent is not limited. However, it is incorporated at 0.05 to 10 mols per mol of the sulfur-containing compound represented by formula (2), preferably 0.05 to 5 mols, more preferably 0.5 to 3 mols.
The ((1)-b) process is more preferable to produce the acrylate ester compound represented by formula (1) in which X1 and X2 are each a sulfur atom.
The acrylate ester compound represented by formula (1) can be produced by reacting the sulfur-containing compound represented by formula (2), in which X1 and X2 are each a sulfur atom, with a halopropionic acid or its acid halide to produce a halopropionic ester compound, and then by dehydrohalogenating the product ester. Such a process is disclosed by, e.g., Japanese Patent Application Laid-open No. 10-67736.
When the acrylic ester compound of the present invention represented by formula (1) is produced, it is preferable to use a polymerization inhibitor to prevent polymerization of the product during or after the reaction process.
Examples of the polymerization inhibitors include known compounds, e.g., 2,6-di-tert-butyl-cresol, 4-methoxy phenol, hydroquinone and phenothiazine. Quantity of the polymerization inhibitor is not limited. However, it is normally incorporated at 0.01 to 5% by weight on the starting mixture in the reaction system or reaction product, preferably 0.05 to 3% by weight.
On completion of the reaction, the acrylic ester compound of the present invention represented by formula (1), as the reaction product, can be suitably isolated from the reaction system by a known operation or treatment procedure (e.g., neutralization, solvent extraction, water washing, fractionation or distillation to remove the solvent). Moreover, it may be further separated and/or purified, as required, to produce a higher-purity compound by a known procedure (e.g., chromatography, adsorption with the aid of activated carbon or the like, or recrystallization).
Next, the polymerizable composition containing, as the essential component, the acrylic ester compound of the present invention represented by formula (1), will be described in detail.
The polymerizable composition of the present invention, containing as the essential component the acrylic ester compound of the present invention represented by formula (1), and a polymerization initiator. The polymerization initiator is a compound which initiates polymerization of the polymerizable compound by light, heat or the like.
The polymerizable composition may be composed of the individual acrylic ester compound, or 2 or more of the different compounds represented by formula (1).
Moreover, the polymerizable composition of the present invention may contain one or more known polymerizable compounds (photopolymerizable or/and thermally polymerizable monomer(s) or oligomer(s)) other than the acrylic ester compound represented by formula (1), as required, within limits not harmful to the intended effect of the present invention.
Quantity of the acrylic ester compound represented by formula (1) in the polymerizable composition is not limited. However, it is normally incorporated at 10% by weight or more on the whole polymerizable composition, preferably 20% or more, more preferably 30% or more, still more preferably 50% or more.
The polymerization initiator is not limited for the polymerizable composition of the present invention, and may be selected from known initiators for photopolymerization or thermal polymerization.
The photopolymerization initiators useful for the present invention include: carbonyl compounds, e.g., benzophenone, 4-methylbenzophenone, 4,4xe2x80x2-dichlorobenzophenone, 2,4,6-trimethylbenzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-(4-methyl-phenylthio)benzophenone, 3,3-dimethyl-4-methylbenzophenone, 4-(1,3-acryloyl-1,4,7,10,13-pentaoxa-tridecyl)benzophenone, 3,3xe2x80x2,4,4xe2x80x2-tetra(tert-butylperoxy-carbonyl)benzophenone, 4-benzoyl-N,N,N-methylbenzene-methanaminium chloride, 2-hydroxy-3-(4-benzoylphenoxy)N,N,N-trimethyl-1-propanaminium chloride, 4-benzoyl-N,N-dimethyl-N-[(2-(1-oxo-2-propenoxy)ethyl)benzene methanaminium bromide, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzene methanaminium bromide, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-hydroxy-3-(3,4-dimethyl-9-oxo9H-thioxanthon-2-yloxy)-N,N,N-thioxanthon-2yloxy)-N,N,N-trimethyl-1-propanaminium chloride and 2-benzoylmethylene-3-methylnaphtho(1,2-d)thiazoline; dicarbonyl compounds, e.g., benzyl, 1,7,7-trimethyl-bicyclo[2.2.1]heptane-2,3-dione (commonly referred to as camphorquinone), 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 9,10-phenanthrenequinone and xcex1-oxobenzene methyl acetate; acetophenone-based compounds, e.g., acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropyl-phenyl)-2-hydroxy-2-methylpropan-1-one, 1-[4-(2-hydroxy-ethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one, 1-hydroxy-cyclohexylphenyl ketone, dimethoxyacetophenone, diethoxyacetophenone, dimethoxy-1,2-diphenylethan-1-one, 2,2-diethoxy-1,2-diphenylethan-1-one, 1,1-dichloro-acetophenone, N,N-dimethylaminoacetophenone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinolpropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime and 3,6-bis(2-methyl-2-morpholinopropanoyl)-9-butylcarbazole; benzoin ether-based compounds, e.g., benzoin, benzoinmethyl ether, benzoinethyl ether, benzoinisopropyl ether, benzoin-n-butyl ether and benzoinisobutyl ether; aryl phosphine oxide-based compounds, e.g., 2,4,6-trimethylbenzoyldiphenyl phosphine oxide and bis(2,6-dichlorobenzoyl)-(4-n-propylphenyl)phosphine oxide; amino carbonyl compounds, e.g., methyl 4-dimethylamino-benzoate, ethyl 4-dimethylaminobenzoate, n-butoxyethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-dimethylaminoethylbenzoate, 4,4xe2x80x2-bisdimethylamino-benzophenone (Michler""s ketone), 4,4xe2x80x2-bisdiethylamino-benzophenone and 2,5xe2x80x2-bis(4-dimethylaminobenzal)-cyclopentanone; halogen compounds, e.g., 2,2,2-trichloro-1-(4xe2x80x2-tert-butylphenyl)ethan-1-one, 2,2-dichloro-1-(4-phenoxyphenyl)ethan-1-one, xcex1,xcex1,xcex1-tribromomethylphenylsulfone 2,4,6-tris(trichloromethyl)triazine, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)triazine 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)triazine, 2,4-bis(trichloromethyl)-6-piperonyl-triazine, (2,4-bis(trichloromethyl)-6-(3,4-methylenedioxyphenyl)-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-triazine, 2,4-bis(trichloromethyl)-6-[2-(5 5-methylfuryl)ethylidyne]triazine and 2,4-bis(trichloromethyl)-6-[2-furylethylidyne]triazine; and 9-phenylacridine, 2,2xe2x80x2-bis(o-chlorophenyl)-4,4xe2x80x2,5,5xe2x80x2-tetraphenyl-1,2-biimidazole, 2,2-azobis(2-aminopropane)-dihydrochloride, 2,2-azobis[2-(imidazolin-2-yl)propane]-dihydrochloride, xcex7-5-2-4-(cyclopentadienyl)-(1,2,3,4,5,6,xcex7)-(methylethyl)-benzene]iron (II) hexafluorophosphate and bis(cyclopentadienyl)bis[2,6-difluoro-3-(1H-pyl-1-yl)phenyl]titanium, all of which are known compounds. They may be used either singly or in combination.
The photopolymerization initiator, when used, is incorporated at 0.001 to 10 parts by weight per 100 parts by weight of the polymerizable compound(s) [the acrylic ester compound represented by formula (1) and one or more known polymerizable compounds used, as required], preferably 0.01 to 5 parts, more preferably 0.01 to 3 parts, still more preferably 0.01 to 1 part.
The thermal polymerization initiators useful for the present invention include: peroxides, e.g., benzoyl peroxide, p-chlorobenzoyl peroxide, diisopropyl peroxycarbonate, di-2-ethylhexyl peroxycarbonate and tert-butylperoxypivalate; and azo compounds, e.g., azobisisobutylonitrile.
The thermal polymerization initiator, when used, is incorporated at 0.001 to 10 parts by weight per 100 parts by weight of the polymerizable compound(s) [the acrylic ester compound represented by formula (1) and one or more known polymerizable compounds used, as required], preferably 0.01 to 5 parts, more preferably 0.01 to 3 parts, still more preferably 0.01 to 1 part.
The known polymerizable compounds which can be used together with the acrylic ester compound represented by formula (1) for the polymerizable composition of the present invention include a variety of known polymerizable monomers, such as mono- and poly-valent (meth)acrylates, e.g., methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ethylcarbitol (meth)acrylate, lauryl (meth)acrylate, tetracyclododecyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, N-n-butyl-O-(meth)acryloyloxyethylcarbamate, acryloyl morpholine, trifluoroethyl (meth)acrylate, tribromobenzyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2-bis(4-acryloyloxyphenyl)-propane, 2,2-bis(4-methacryloyloxyphenyl)propane, bis(4-acryloyloxyphenyl)methane, bis(4-methacryloyloxy-phenyl)methane, 4,4xe2x80x2-bis(2-acryloyloxy)phenyl sulfide, 4,4xe2x80x2-bis(2-methacryloyloxy)phenyl sulfide, 2,2-bis(4-acryloyloxyethoxyphenyl)propane, 2,2-bis(4-methacryloyl-oxyethoxyphenyl)propane, 2,2-bis[4-(2-acryloyloxy-propoxy)phenyl]propane, 2,2-bis[4-(2-methacryloyloxy-propoxy)phenyl]propane, bis(4-acryloyloxyethoxyphenyl)methane, bis(4-methacryloyloxyethoxyphenyl)methane, bis[4-(2-acryloyloxypropoxy)phenyl]methane, bis[4-(2-methacryloyloxypropoxy)phenyl]methane, 4,4xe2x80x2-bis(2-acryloyloxyethoxy)phenyl sulfide, 4,4xe2x80x2-bis(2-methacryloyloxyethoxy)phenyl sulfide, 4,4xe2x80x2-bis(2-acryloyloxypropoxy)phenyl sulfide, 4,4xe2x80x2-bis(2-methacryloyloxypropoxy)phenyl sulfide, 4,4xe2x80x2-bis(2-acryloyloxyethoxy)phenyl sulfone, 4,4xe2x80x2-bis(2-methacryloyloxyethoxy)phenyl sulfone, 4,4xe2x80x2-bis(2-acryloyloxypropoxy)phenyl sulfone, 4,4xe2x80x2-bis(2-methacryloyloxypropoxy)phenyl sulfone, di(meth)acrylate of ethylene or propylene oxide adduct of 2,2xe2x80x2-bis(4-hydroxyphenyl)propane, di(meth)acrylate of ethylene or propylene oxide adduct of bis(4-hydroxy-phenyl)methane, di(meth)acrylate of ethylene or propylene oxide adduct of 4,4xe2x80x2-dihydroxyphenyl sulfide, trimethylolpropane tri(meth)acrylate, dipentaerythritol pentaacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylol tetraacrylate, dipentaerythritol hexaacrylate, 2-(meth)acryloyloxyethyl trisisocyanurate and (meth)acryloxypropyl tris(methoxy)silane; epoxy (meth)acrylates obtained by acting a (meth)acrylic acid compound on a known mono- or di-valent epoxy compound such as phenol glycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, resorcin diglycidyl ether, hydroquinone diglycidyl ether, bis(4-hydroxyphenyl)methane (commonly referred to as bisphenol F) diglycidyl ether, 2,2-bis(4-hydroxyphenyl)-propane (commonly referred to as bisphenol A) diglycidyl ether, 4,4xe2x80x2-bishydroxyphenyl sulfide diglycidyl ether, 4,4xe2x80x2-bishydroxyphenyl sulfide (commonly referred to as bisphenol S) diglycidyl ether, 3,3xe2x80x2,5,5xe2x80x2-tetramethyl-4,4xe2x80x2-biphenol diglycidyl ether and tris(2,3-epoxypropyl)-isocyanurate; epoxy (meth)acrylates obtained by acting a (meth)acrylic acid compound on a known epoxy resin such as phenol novolac type, cresol novolac type, phenol zyrock type or bisphenol type epoxy resin; vinyl compounds, e.g., vinyl benzene, divinyl benzene, trivinyl benzene, isopropenyl benzene, diisopropenyl benzene, triisopropenyl benzene, N-vinyl pyrrolidone and N-vinyl caprolactam; compounds containing an allyl group, e.g., ethylene glycol diallyl carbonate, triallyl trimellitate ester and triallyl isocyanurate; and a variety of known polymerizable olifomers, e.g., urethane (meth)acrylates, epoxy (meth)acrylates, polyester (meth)acrylates and polyether (meth)acrylates.
Quantity of those is not limited. However, it is normally incorporated at 300 parts by weight or less per 100 parts by weight of the acrylic ester compound of the present invention, preferably 200,parts or less, more preferably 100 parts or less, to secure the effect of the present invention.
The polymerizable composition of the present invention is produced by mixing and dissolving the acrylic ester compound of the present invention represented by formula (1), and, as required, one or more of the above-described known polymerizable compounds and the above-described polymerization initiator. The polymerizable composition may be filtered to remove impurities and/or foreign matter and, moreover, sufficiently defoamed under a vacuum, as required, before being polymerized and cured.
The starting mixture for the polymerizable composition may be incorporated one or more of a variety of known additives, as required, within limits not harmful to the effect of the present invention. These additives useful for the present invention include an internal releasing agent, a light stabilizer, an ultraviolet ray absorber, an antioxidant, a colorant/pigment (e.g., cyanine green and cyanine blue), a dye, a flow-adjusting agent, and an inorganic filler (e.g., talc, silica, alumina, barium sulfate or magnesium oxide).
The cured product of the present invention and optical component made of the cured product are obtained by polymerizing and curing the polymerizable composition. They have been suitably produced by a variety of known methods, typically by heat- or light-initiated radical polymerization of the polymerizable composition put in a mold.
One of the typical molds for the polymerization is composed of two mirror-polished molds having a gasket (e.g., of polyethylene, ethylene/vinyl acetate copolymer or polyvinyl chloride) therebetween. A set of two molds is a combination of glass and glass plates, glass and plastic plates or glass and metallic plates, among others. They may be adhered to each other via an adhesive tape (e.g., of polyester), instead of via a gasket of the above-described soft, thermoplastic resin (e.g., polyethylene, ethylene/vinyl acetate copolymer or polyvinyl chloride). The mold may be treated by a conventional procedure, e.g., releasing.
The radical polymerization may be effected by the aid of heat (thermal polymerization), light such as ultraviolet ray or visible ray (photopolymerization), activated energy ray such as gamma ray, or their combination.
When the photopolymerization is adopted, the cured product released out of the mold or the optical component thereof may be annealed to remove the internal stress or strain.
Of these methods, the photopolymerization is preferable in view of productivity for production of the optical component of the present invention, because it can cure the composition in several seconds to several minutes. This compared with several hours to more than 10 hours needed by the thermal polymerization.
The temperature for the heat polymerization is not limited, because it depends on polymerization conditions, e.g., type of polymerization initiator adopted. However, it is normally in a range from 25 to 200xc2x0 C., preferably 50 to 170xc2x0 C.
The optical lens can be molded by casting in which the polymerizable composition is polymerized in a mold by the aid of light and/or heat, as disclosed by, e.g., Japanese Patent Laid-open Publication Nos. 60-135901, 10-67736 and 10-130250. More specifically, the polymerizable composition prepared in the above-described manner to contain the acrylic ester compound of the present invention represented by formula (1), is put in a mold where it is suitably polymerized normally with the aid of light, after being defoamed as required by an adequate procedure. When the thermal polymerization is adopted, it can be suitably carried out by heating the polymerizable composition slowly from low to high temperature.
The optical lens produced may be annealed as required, after being cured. It may be further treated physically or chemically by a known procedure, e.g., surface polishing, antistatic treatment, hard coating, reflection free coating, dye treatment or light modulation (for example, photochromic lens treatment), as required, for various purposes, e.g., preventing light reflection, imparting hardness, improving wear resistance, imparting anti-fogging property or imparting fashinability.
For production of a substrate for information recording medium, e.g., optical disk, the polymerizable composition prepared in the above-described manner to contain the acrylic ester compound of the present invention represented by formula (1), is injected into a cavity for disk substrates, where it is polymerized by a known procedure, e.g., radical polymerization followed, as required, by heating for post-treatment (disclosed by, e.g., Japanese Patent Laid-open Publication Nos. 58-130450, 58-137150 and 62-280008), photopolymerization in a mold with glass plates on both sides (disclosed by, e.g., Japanese Patent Laid-open Publication No. 60-202557), or thermal polymerization of liquid resin in a vacuum mold or under pressure after it is injected into a mold (disclosed by, e.g., Japanese Patent Laid-open Publication No. 60-203414).
The cured product of the photopolymerized composition of the present invention and the optical component thereof can be produced in a shorter time of several minutes to several hours for polymerization (curing) and molding than the conventional thermosetting optical resin represented by polydiethylene glycol diallyl carbonate or polythiourethane. Higher productivity is one of the characteristics of the present invention. The cured product and the optical component thereof of the present invention are also characterized by high transparency and higher refractive index than that of the conventional thermosetting resin, while involving practically no problems in mechanical and thermal characteristics. The optical component of the present invention can find wide applications, e.g., various types of plastic optical lenses represented by vision-correcting spectacles lenses and pickup lenses, optical disk substrates for information recording media, plastic substrates for liquid crystal cells, and various transparent coating materials, e.g., anti-reflective coating.
The cured product or optical component of the present invention can be produced efficiently in a short time by photopolymerization or the like; is high in refractive index and good in optical characteristics (e.g., transparency and Abbe number), thermal characteristics (e.g., thermal deformation temperature) and mechanical characteristics (e.g., impact resistance; and hence is useful for various purposes, e.g., various types of plastic lenses represented by vision-correcting spectacles lenses, transparent substrate materials for optical information recording media and liquid crystal cells, various transparent coating materials, e.g., those for anti-reflective coating, various transparent sealants, e.g., those for light-emitting diodes (LEDs), and dental materials.
The present invention will be described in more detail by EXAMPLES, which by no means limit the present invention.
⋄ Synthesis of the Sulfur-Containing Compound of the Present Invention Represented by Formula (2-a)